It’s the difference between dropping an envelope in a blue mailing box with only the destination address vs registering on usps.com to print a label. Probably D

It’s the difference between dropping an envelope in a blue mailing box with only the destination address vs registering on usps.com to print a label. Probably Due to the Unabomber, they stopped accepting large packages in the anonymous blue postal bins that were paid by stamps. Phone companies can CHOOSE to stop routing calls without more identity/registration from the caller but it’s just not implemented, maybe for legacy compatibility reasons. I believe for some countries on twilio, phone number registrations require additional verification, but for the US you just need credit on twilio.